The emergence of mumps after the COVID-19 pandemic in Pakistan: Time to consider MMR vaccination strategies
Authors: Muhammad Suleman Rana, Muhammad Usman, Muhammad Masroor Alam, Muhammad Tahir, Aamer Ikram, Syed Sohail Zahoor Zaidi, Muqarrab Kashif, Massab Umair, Muhammad Anas, Nadeem Ullah, Muhammad Salman
Journal: Journal of Infection (2023)

An interesting article recently published in this journal, entitled" Changes of Mycoplasma pneumoniae prevalence in children before and after COVID-19 pandemic in Henan, China" by Xiaojuan Li and colleagues.1Li X. Li T. Chen N. Kang P. Yang J. Changes of Mycoplasma pneumoniae infection in children before and after COVID-19 pandemic in Henan, China.J Infect. 2023; (1-S0163-4453(22)00705-8; doi:10.1016/j.jinf.2022.12.015. Online ahead of print)Google Scholar Authors reported that the COVID-19 pandemic has an impact on the Mycoplasma pneumoniae infection in children. We completely agreed that the decline in majority of respiratory diseases documented during the COVID-19 pandemic. However, here we would like to report the unprecedented rise in mumps outbreaks in Pakistan after the COVID-19 pandemic. Mumps is an acute viral illness that clinically presents with fever, headache, tiredness, loss of appetite, and parotitis (inflammation of salivary glands). However, sometimes mumps infection may present with only nonspecific respiratory symptoms. Generally, the disease is mild, but serious complications such as Orchitis, Oophoritis, pancreatitis, encephalitis, meningitis, and deafness can occur.2Clemmons N.S. Redd S.B. Gastañaduy P.A. Marin M. Patel M. Fiebelkorn A.P. Characteristics of large mumps outbreaks in the United States, July 2010–December 2015.Clin Infect Dis. 2019; 68: 1684-1690Crossref PubMed Scopus (17) Google Scholar Worldwide, mumps is not as well controlled as compared to measles and rubella. From 1999–2019, on average, about 500,000 mumps cases were reported to the World Health Organization annually.3Mariel Marlow, P., MPH; J. Leung, MPH; M. Marin, MD; C. Hickman, PhD; N. Clemmons, MPH; L. Shepersky, et al.; Huong Pham, MPH; Manisha Patel, MD, MS, Manual for the surveillance of vaccine preventable diseases. 2021.Google Scholar In this report, we highlight the largest mumps outbreak in Pakistan which occurred in 2022 and is continuing in 2023. Pakistan had the sporadic transmission of mumps from 1991 to 2009 and the first localized outbreak of mumps was documented in 2010.4Asghar H. Zaidi S.S. Ghafoor A. Anwer F. Mumps outbreak in hostel.J Pak Med Assoc. 1992; 42 (-281): 281Google Scholar Localized mumps outbreaks in Pakistan were reported from 2010-2021. After the COVID-19 pandemic in 2022, the mumps outbreak surpassed all previous records. From 1 January to 31 December 2022, a total of 19,444 mumps cases had been officially recorded from all provinces of the country, mostly in Khyber Pakhtunkhwa (72.5%), Punjab (8.7%), Sindh (9.8%), Balochistan (2.1%), Islamabad (2.1%), Azad Jammu& Kashmir (1.6%), and Gilgit Baltistan (2.2%). Most cases had mild symptoms however, swelling of salivary glands and fever were noticed in 93% and 47% of cases respectively. The overall median age of mumps-infected patients was 21 years (range, 3-46 years). Among reported mumps cases, 65% occurred among males and 35% among females' individuals. By age group, cases occurred most frequently among children aged 1-5 years (50%), followed by children aged 5 to 10 years (35%), 11-20 years (4.5%), and >20 years (9.8%). Overall, 89.5% of reported cases were from the < 20 years age group. It is speculated that the actual number of cases may be much higher than reported because 20%-30% of mumps cases remain asymptomatic so people can spread the virus without knowing they have it. At least 117 patients have been hospitalized in the outbreak so far, but none have died of the viral illness. Most of the cases were reported during the Months of July-December 2022. All reported cases contained some close contact involvement and some sporadic cases reported from a different location had an epidemiological link with outbreak cases. Measles and Rubella are notifiable diseases in Pakistan and Measles containing vaccines (MCV1 and MCV2) were introduced in the schedule of the routine immunization program in 1974 and 2009 respectively. However. The rubella vaccine in the form of MR has been included in the routine immunization program in 2021.5Rana M.S. Usman M. Alam M.M. Ikram A. Salman M. Umair M. The world's largest measles-Rubella vaccination campaign in Pakistan: time to invest in routine immunization.Hum Vaccines Immunother. 2022; 182080444Crossref Scopus (1) Google Scholar Mumps is not a notifiable disease in Pakistan due to the low disease burden recorded from 1991-2021 (Fig. 1). The current largest outbreak of mumps in Pakistan provided scientific evidence to public health authorities to include the mumps in the list of notifiable diseases. Global and regional mumps incidence is challenging to estimate as mumps is not a notifiable disease in many countries including Pakistan. As of 2019, the mumps vaccine is routinely used in 122 of 194 (63%) countries and the mumps incidence is still much higher in countries that do not have routine mumps vaccination.3Mariel Marlow, P., MPH; J. Leung, MPH; M. Marin, MD; C. Hickman, PhD; N. Clemmons, MPH; L. Shepersky, et al.; Huong Pham, MPH; Manisha Patel, MD, MS, Manual for the surveillance of vaccine preventable diseases. 2021.Google Scholar As of June 2020 Pakistan, Afghanistan, India, and Japan did not have the mumps vaccine included in their national immunization programs. The mumps vaccine is given along with the vaccine of Measles and Rubella in the form of MMR. It is reported that a 78% risk reduction against mumps following one dose rises to 88% after receiving two doses of MMR vaccine.6A mumps outbreak among fully vaccinated people: Available at; https://www.scientificamerican.com/article/a-mumps-outbreak-among-fully-vaccinated-people/. 2020, 10 January 2023.Google Scholar The strategy to control mumps is to have the measles-mumps and rubella (MMR) vaccination as part of a national immunization program. Alongside vaccination, the isolation of infected individuals is the second approach that helps to control the outbreak. In the meantime, coordinated local and global efforts are needed to promote the availability and proper use of vaccines in low-income countries including Pakistan. In the past few years, vaccine hesitancy has led to a decrease in the uptake of many vaccines and currently, the COVID-19 pandemic imposed a negative impact on vaccination. During the COVID-19 pandemic, a general reduction of vaccination coverage is reported across the globe. Measles and Rubella are also endemic in Pakistan with thousands of cases and hundreds of deaths reported annually. The perfect solution to these continued threats of illness imposed by Measles, Mumps, and Rubella which are untreatable but readily preventable diseases is compliance with recommendations for the administration of the measles-mumps-rubella vaccine. MMR vaccine is very effective at protecting people against measles, mumps, and rubella, and preventing the complications caused by these diseases as well. Therefore, the health authorities in Pakistan must consider the MMR immunization strategies on the bases of current evidence to save Pakistani children from Measles, mumps, and Rubella at the same time. No funding sources.